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Fertility control for feral pigeons? Wildlife academics gather in York to debate using contraception to manage animal numbers

Posted on 13 June 2024

Leading wildlife academics from around the world are set to gather in York for a major workshop exploring how contraception could be used as a humane alternative to controlling animals that have widespread ecological and economic impacts.

Numbers of pigeons are rising in the UK and across the world

These impacts include the spread of disease, crop and forestry damage, reduction of native plant and animal species and road traffic accidents.

As part of the interactive workshop being held at the University of York, experts and participants will discuss how best to limit numbers of grey squirrels, wild boar, deer, feral goats, pigeons, rats and other wildlife to mitigate these impacts 

Ecologically critical

A key approach to be highlighted will be the need to develop contraceptives for animals. These contraceptives would provide conservationists and farmers with a means to curtail animal numbers in a non-lethal, more publicly acceptable way.

According to Dr Giovanna Massei, Europe Director, Botstiber Institute of Wildlife Fertility Control and Professor at the University of York, the problem is likely to get much worse over the coming years and is a pressing and critical ecological issue both here in the UK and around the world.

Developing a consensus

To help solve some of the vital challenges, Dr Massei is organising the 1st Workshop on Wildlife Fertility Control: What now? What next? Where to? that is taking place at the University of York on June 17 and June 18.

Dr Massei explained: “Unless new and humane measures to curtail the numbers of some animal populations are developed in the near future then conflicts between humans and wildlife are going to grow and grow.

Diverse challenges

"In the modern world there are so many conflicts between people and wild creatures but there is no consensus on how best to manage wildlife numbers.”

Dr Massei explained: “There are many facets contributing to this challenge. The number of hunters is declining throughout the world and many of the so-called game species (deer, wild boar) are increasing. Reintroduced native species like the beaver in the UK and non-native species such as parakeets and raccoons are also growing in numbers and range, in parallel with public demand to employ non-lethal methods to manage these populations. 

Practical applications

“The use of poison, such as rodenticides traditionally used to kill rats and mice is increasingly restricted or even banned  to avoid affecting birds of prey and other animals. This means we must identify alternatives to the traditional ways to manage wildlife. Fertility control, alone or combined with traditional methods, could provide solutions.

This event in York will mostly explore the practical applications of wildlife fertility control in Europe. The first day will be dedicated to talks about wildlife species and contexts that might be suitable for  using  fertility control. The second day will focus on group discussions on the challenges and opportunities of implementing wildlife fertility control for different species across a range of contexts. Attendees will include representatives from public and private sectors, academia, practitioners and non-government organisations.

Disease transmission

Pigeons provide an illustration of the issues involved and will be discussed at the workshop. Their numbers are rising across the world and in the UK, and the birds are very common in towns, cities and in urban areas. These large numbers of pigeons can overwhelm places, leading to hygiene issues, unpleasant odours, and increased risk of disease transmission. And when pigeons are consistently fed, they may become extremely territorial and aggressive towards each other.

Pigeons carry a variety of diseases such as Ornithosis, Listeria and E-coli that can be transmitted to humans not only from pigeon droppings but also the birds themselves. Three human diseases, histoplasmosis, cryptococcosis and psittacosis are linked to pigeon droppings. When dry, pigeon droppings become airborne in small particles, this can lead to respiratory complaints such as psittacosis. These diseases can be dangerous or life-threatening to people with certain conditions, like asthma or weakened immune systems.

Expensive issues

When pigeons nest in buildings, they excrete a great amount of faeces which is messy and dangerous, leading to risks of falls. It can make pavements, fire exits, car parks and other areas dangerous for foot traffic and the public liability risk that goes with this, particularly for businesses and commercial properties.

Feral pigeon droppings can foul buildings too, creating unwanted corrosive damage. Pigeon faeces is highly acidic and can cause serious damage to buildings to corrode and erode metals, stonework, and brickwork. When pigeons nest in gutters or downpipes this causes water backup, flooding, leaks and other water-related problems and pigeon faeces can block gutters and drainage.

Shifting opinion

Dr Marco Pellizzari, a global expert on feral pigeons and alumni of the University of Bologna, is travelling from Italy to York to share his research at the conference. He explained: “Pigeons can reproduce up to eight times a year and have a life expectancy of five years, which means it is no surprise their population is growing so rapidly. And the feeding of these birds by local people has also contributed to the growth in numbers. They are well loved still, but public opinion is now shifting towards controlling numbers.”

Preventing pigeons from breeding is the most humane way to limit numbers, Dr Pellizzari believes. He explained: “The overpopulation of pigeons is creating numerous issues in the public space. They pick open bin bangs which litters our pavements, they defecate on monuments, buildings and sometimes on people's heads - now there is a broad agreement that we need to limit their numbers and fertility control such as Ovistop is the best answer.”

Evidence-based solutions

The contraception can be administered manually or by an automatic feeder. It works by inhibiting eggs hatchability in treated pigeons. 

Dr Pellizzari added: “The research I am sharing in York is conclusive that fertility control is an effective method, particularly when combined with other methods such as ban on feeding pigeons, of controlling numbers of feral pigeons. This has the best outcomes for our towns and cities, but also the birds themselves. We have previously found that overcrowding results in stress in birds, that leads to parasites in pigeons populations with negative effects on their health and undermines colonies. Fertility control is the best way to develop a peaceful coexistence between humans and wild birds.”

Creating coexistence

This coexistence and a peaceful way for humans and wildlife to live together is the ultimate goal of the conference, Dr Massei explains: “We need to control numbers in ways that are publicly supported, and that means relying on non-lethal methods which are popular with the public but we must also make the public aware of what implementing fertility control for wildlife really means

“In today's human-dominated world, safe spaces for wildlife are becoming scarcer and many populations of wide-ranging animals are forced to inhabit the same spaces and share resources with people. We are hopeful that by bringing so many international experts to York to discuss this we can create a new framework and sense of collective responsibility for developing peaceful coexistence between humans and wildlife.”

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